PanaVise Standard Base.
Accepts any 5/8" (15.9mm) diameter shaft. Single control knob and exclusive 'split-ball' locks head firmly in place.
Base features 4.3125" (109.5mm) bolt circle countersunk for three 1/4" (6.3mm) flat-head screws (not included)
Height: 3.75" (95.2mm) Weight: 1.4 lbs. (0.6kg)